1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and devices used for processing seismic data, and, more particularly, to methods and devices to process stacked slip-sweep data.
2. Discussion of the Background
Due to continued interest in developing new oil and gas production, large financial, technical and human resources are used for seismic surveys capable of generating a profile (image) of underground geophysical structures. While this profile does not provide an accurate location for oil and gas, it suggests, to those trained in the field, the presence or absence of oil and/or gas.
In seismic surveys, a seismic source generates seismic waves that penetrate the underground structure and are reflected back by interfaces between layers through which the seismic waves propagate with different velocities. Seismic receivers detect the reflected waves that carry information about the underground structure (e.g., location of the interfaces). Conventionally, a new shot is not fired while the seismic receivers still detect reflections from a previous shot.
Due to the high cost of seismic surveys, there is a continuous desire to improve productivity in seismic data acquisition, i.e., shortening the duration of seismic surveys. However, improving productivity should not result in degradation in data processing results' quality and reliability. Methods aimed at shortening the duration of seismic data acquisition explored techniques of firing shots simultaneously but far apart, overlapping seismic records corresponding to incident seismic waves having different phases, or overlapping records corresponding to different frequency ranges.
For example, according to a conventional method of firing land seismic sources, a “shot” includes four sweep segments of four seconds, during which incident seismic waves are generated, each sweep segment being followed by six seconds of listening time while seismic receivers detect and record data related to incident wave reflections. In the example above, the four sweep segments followed by listening time last a total time of 40 seconds. Afterwards, during a time period known as “MoveUp”, the seismic source(s) is/are moved to another shot location. For example, the “MoveUp” may last about 30 seconds.
Accordingly, it would be desirable to provide systems and methods capable of processing acquired seismic data faster while simultaneously maintaining or improving the quality of the processed results.